EFFECTS OF AN ACTIVITY PROGRAM ON SPONTANEOUS PHYSICAL ACTIVITY, AEROBIC CAPACITY, BODY COMPOSITION, AND PERCEIVED PHYSICAL COMPETENCE IN OBESE CHILDREN

Abstract

The purpose of this study was to evaluate changes in spontaneous physical activity, aerobic capacity, body composition, and perceived physical competence after an 8-week after-school activity program in obese, prepubescent children. Participants were 30 children (15 intervention and 15 control) between 8 and 11 years of age. Physical activity ws assessed by Tritrac accelerometers and Digiwalker pedometers for five consecutive days before and after the physical activity program. Social cognitive theory provided the theoretical basis for the design of the activity program. The intevention group participated in bicycling, inline skating, and active games. Cohen's delta (d) was used to estimate the size of the change from pretraining to posttraining for each group. The intervention and control groups both demonstrated moderate decreases in objectively measured physical activity after the 8-week training program (d = 0.53 and 0.50, respectively). This can be partially explained by seasonal variations in activity patterns of children. The intervention group improved maximal treadmill time by 34 seconds (d = 0.41), while the control group improved by 14 seconds (d = 0.14). No meaningful changes were noted in percent fat or body mass index (BMI) for the intervention group (d = 0.09 and 0.14, respectively). For the control group, the decrease in percent fat (d = 0.29) and the increase in BMI (d = 0.14) were small. On the perceived competence questionnaires, boys in the intervention group reported greater increases than girls in the intervention group and control group participants. In summary, the 8-week physical activity program resulted in no change in spontaneous physical activity relative to the control group. Thus, intervention group participants did not compensate for the increased levels of physical activity received from the activity program by decreasing their level of physical activity outside the program. Because perceived competence is a determinant of physical activity, the small improvement in perceived competence could be meaningful, especially for boys.